Cracks around keel where it meet the hull. are these / is this bad?

[woozy-UK]

as some may recall i ran aground last june. i lost my rudder (which im still trying to source a replacement for before June this year)

a young member of the club is at university doing boat building course and for his course he asked if he could survey my boat. he came up with these worrying notes-

The hull seems fine, no real issues. You have cracking all the way around the top of the keel where it attaches to the hull (I'm assuming from where u ran aground). When I lifted the floor boards on top of the keel the bolts seemed fine and not rusty which us good, however there was a few puddles of water in there as well as more cracking around the hull where the keel attaches. Also there is a transverse stiffener at the back of the keel which has cracked right down the middle (from where the back of the rudder would of pushed up into the hull) so that will need to have an eye kept on it.

The transverse stiffener is a thick piece of laminate that goes from left to right. If you have had it on the water for a few months and been sailing quite a lot since then, then nothing is terribly wrong with it and it isn't going to leak or sink or anything so don't worry. For the keel, if u are able to get it lifted at all so it's not sitting on the keel, you can then give it a big push to see if there

i never noticed the cracks before. today i took photos. pease can you all havea gander and give me your opinions and solutions please

many thanks

john

 

[MoodySabre]

My keel attaches differently to yours (see pic)
View attachment 41078

There is always a visible line where the hull meets the cast iron keel and this is filled with sealant. So I wouldnt call that a 'crack'. But I would be more concerned that it is visible inside the boat with other obvious damage. I'd get a surveyor on the case pdq as this may be part of your insurance claim for the grounding.

 

[30boat]

There is too much old antifoul to know wether the cracks are superficial or deep.At the front of the keel there appear to be cracks on the flange but again there's too much paint.The transverse stiffener(floor) that has cracked shows that was a serious upwards deflection of the bottom when the keel hit the sea floor.That alone points to serious structural damage.I'd advise the bottom and top area of the keel to be stripped of paint so that the full extent of the damage can be assessed.I don't agree with the comment that since the boat has been sailing for some time there's nothing to worry about.That's nonsense IMHO.

 

[johnlilley]

Well, firstly there appears to be a thick covering of brittle antifoul and this will crack in almost all circumstances, especially when there has been an incident that may have shaken the boat and keel but in itself they do not confirm that there is grp cracking at this stage. Any further checking externally will require the antifoul coatings to be removed and check for hairline cracks in the laminate.

Externally I can see cracks under the antifoul emanating from the keel flange corners on picture 1. These are not easy to see but they are there I think. These are not uncommon as they often stem from original fitting trying to pull the keel up to the hull but very slight variance in profiles of keel casting and hull shape. The hull has to give ultimately and this causes cracks in the gel coat from day one. Any subsequent abnormal strain can obviously impact on these already stressed areas,

However I would be concerned about what appears to be a crack on photo 2 that is visible at the top left about 1/3 of the way from the left and runs down. Until the antifoul is removed and the exposed gel coat checked, I woul not leave this unchecked. It might well be nothing, but it does have the appearance of a grp crack.

Internally the cracks reported could just be gel wash that has cracked and if that is the case then not that important but again this would have to removed to check beneath bearing in mind the stressing that has occurred.

Some close inspection would be necessary at the areas surrounding the keel bolts looking for hairline cracks,

The athwartships floor or support that is cracked would be considered structural and a sign that the underside of the hull has been flexed severely. I believe this shoul be reinforced.

I do think that for peace of mind the area should be examined by removal of the antifoul coatings externally now. The hull has possibly not cracked where you see the large cracks in the antifoul, but more likely in places not immediately visible unless you are used to identifying underlying cracks beneath antifoul.

Generally stress cracks in laminate will not quite as expected sometimes, they might not even be easily found as they really are hairline cracks and seldom like the cracks you are looking at on the keel/hull join. However, just because it is only a hairline crack and does not look very large, do not underestimate it, it can be just as weakening as a crack that you can slide an envelope in if it is deep enough.

Spend some more time on close examination and possibly get some advice.

John lilley

 

[30boat]

By the way,what boat is it?

 

[woozy-UK]

thanks for comments. serriously worried now. about task and what it may cost.

boat is an Intro 22.

-

a bit of info on the intro- http://sailboatdata.com/viewrecord.asp?class_id=6281

pic of the boat last year before the accident-

 

[30boat]

thanks for comments. serriously worried now. about task and what it may cost.

boat is an Intro 22.

-

a bit of info on the intro- http://sailboatdata.com/viewrecord.asp?class_id=6281

pic of the boat last year before the accident-

Don't be worried.The beauty of fiberglass is that anything and I mean anything can be repaired.An example.A friend in Macau dropped anchor in front of the yacht club and rowed ashore for a meal.He forgot,or didn't know he should,to check the tides.Result,boat ends up in the surf ,loses the keel overnight and ends up with a gaping hole you could walk through.He was distraught so I took pity on him and told him it was very fixable.Being Chinese he knew everybody there so he had the keel recovered and the boat taken to a local shipyard where they built fishing large boats in wood.Under my direction three workers whith no experience in grp work,rebuilt the bottom and the interior .We then had the boat taken to the navy dock where it was lifted by a hired crane to have the keel refitted.That was in 1994,the boat ,an Eightene 24 is still sailing in Hong Kong waters.

 

[woozy-UK]

hi all.
i cleaned and took photos of the bilge above the keel. there is a what looks to be a substantial crack on the port side, light crack on the other and also through the block that the previous owner put above the back of the keel area.

please can i have your opinions again.

many thanks.

 

[charles_reed]

Well after 30-boats film show I'm still reeling - perhaps needed a voice-over to tell me what I was seeing.

However, to Woozy, what he says is true, grp is eminently patchable. First, to see how bad the cracks really are you need to clear away the old sealant and antifouling.
Only then can anyone suggest how bad it is and how to repair.

 

[TradewindSailor]

It needs a structural repair. Many of these cracks extend well into the structural hull laminate, if no entirely through the hull.

I suggest that you get a qualified surveyor or a recommended and experienced shipwright to specify and oversee the repairs.

I also suggest you get your young club member to see the damage ..... he needs to understand the possible implications of his advice and hopefully it will be valuable experience for him. He really does need to see this.

 

[30boat]

As I see it there is damage to the floor at the aft end of the keel (it's crakced through) and there are serious looking cracks on the laminate along the length of the keel on both sides.Don't despair.It's really easy to repair and you can make it stronger than it was before.It's a small boat with a small keel so I would build a cradle to support the keel steady and lift the boat away from it.Then grind (or my favourite, chisel) away the areas of affected laminate until you find sound laminate.I usually chisel the laminate away because it's more controlable and the whole boat won't be contaminated with horrible fiberglass dust.A good quality chisel kept sharp by a small grinder can remove fiberglass quite effectively and leave a rough surface that's ideal for laminating over.
Make the area around the damage in to a shallow V and relaminate with epoxy and rovings.From the pictures you have plenty of space for some extra floors.You can make them of resin resistant foam or wood ,rounded at the corners to help the rovings conform to the shape.Taper the ends to nothing where they meet the hull sides to avoid creating hard spots.Open up the crakcs from the outside and do the same shallow V shape and laminate ,sand or grind flush and fair.Reatach the keel and your done.Be careful how you support the hull so as not to distort it because the distortion will be locked in by the repairs and you'll have problems making the keel fit again.
Looking at the pictures again I'm afraid you'll need to dismantle the furniture in the way of the cracks.It's a lot of work I know but it's not difficult to do.

 

[PuffTheMagicDragon]

The only way is the proper way and I'm afraid that there is no quick solution. Separate the keel from the hull and remove all traces of sealant, paint and antifouling. I disagree about using an old chisel as this can cause some delamination; I would prefer an angle grinder and a coarse flapdisk. Only then can you see the extent of the damage. I have seen a Jeanneau 29 that had only minute cracks visible around the keel root after a grounding. Further investigation showed that some floors had to be rebuilt. Another case was that of a boat called 'Patches'; hairline cracks on the outside but the hull bottom had to be rebuilt in that area. If I were doing the work I would strengthen the area by way of where the keel is bedded, extending it well athwartships, besides adding more floors as necessary. Unfortunately what you have is not uncommon with the 'modern' trend of adding a separate keel to what is essentially a large dinghy-shaped underbody.

Your problem is relatively easy to get fixed but it does take a lot of effort. BTW, after you finish grinding don't forget to take moisture readings because seawater will have seeped in through the cracks. I agree with getting a proper survey done and also with keeping your 'friend' informed of your findings; you'll be doing him a great favour that I hope he'll appreciate.

 

[oldharry]

Your young friend is right that it is not leaking, and the boat has not sunk. However the structural integrity of the hull, and therefore its strength is possibly quite seriously compromised, and while in normal use it may not matter, even a minor grounding could result in major or even catastrophic failure of the damaged parts of the hull..

You need professional advice as to how to set about repairs.

 

[30boat]

The only way is the proper way and I'm afraid that there is no quick solution. Separate the keel from the hull and remove all traces of sealant, paint and antifouling. I disagree about using an old chisel as this can cause some delamination; I would prefer an angle grinder and a coarse flapdisk. Only then can you see the extent of the damage. I have seen a Jeanneau 29 that had only minute cracks visible around the keel root after a grounding. Further investigation showed that some floors had to be rebuilt. Another case was that of a boat called 'Patches'; hairline cracks on the outside but the hull bottom had to be rebuilt in that area. If I were doing the work I would strengthen the area by way of where the keel is bedded, extending it well athwartships, besides adding more floors as necessary. Unfortunately what you have is not uncommon with the 'modern' trend of adding a separate keel to what is essentially a large dinghy-shaped underbody.

Your problem is relatively easy to get fixed but it does take a lot of effort. BTW, after you finish grinding don't forget to take moisture readings because seawater will have seeped in through the cracks. I agree with getting a proper survey done and also with keeping your 'friend' informed of your findings; you'll be doing him a great favour that I hope he'll appreciate.

I didn't say an old chisel.I said a chisel kept sharp by a small grinder.I've been using this system for many years and providing the chisel is sharpened at regular intervals it doesn't cause delamination.Common sense dictates that the blows from the mallet should be moderate.It's slower than grinding but the benefits are huge.No itchy dust everywhere and the process is much more controlable.I've reinforced the keel area in three boats(my Fulmar,my Peterson30,and a friends Bavaria 30) this way and it all went very well.

 

[Iliade]

Been there, done that!

I'm afraid your hull looks pretty kippered. There is also almost certainly a degree of delamination associated with the visible cracking and consequent water penetration.

High speed tools, eg anything bolted to an angle grinder, are a bad idea as they tend to spread mess and more importantly they can all too easily heat the area, causing more damage. I would second the sharp chisel approach. You will blunt it quickly, so do keep it sharp so that it does little collateral damage. Modern vibrating cutters are pretty good too.

I would work on the premise that the original hull is just a former for your new structure and feather it in over as large an area as possible. Don't skimp.

I used epoxy and variously, directional glass matting, carbon & kevlar matting. I also replaced the floors and made their 'overmoulding' anew. The keel root was the strongest part of the boat after I had finished.

Unfortunately it took nearly a year for my hull to dry out and I'd stripped the gelcoat and tented it...

My 'event' occurred when small old yachts were still expensive. That is no longer the case. You need to make sure that your repair is good enough that you will feel happy with it while free-flying off the wave tops in a force ten. If you cannot do it to that standard, then you should probably consider scrapping the hull, maybe using all of your good bits to bring a poor example of the class up to scratch cheaply. Not advice you may like to hear, but it could save you a long time away from the water. Not to mention a lot of heartache and expense.

If you intend to get it done by a professional, do not let 'Fred who knows how to fibreglass' do it, get it done by a real FRP specialist.

An approach I considered was to make a keel box and lifting keel arrangement then simply bolting it to the hull where the keel used to be. (Over a much larger aperture!)

 

[pampas]

Have you looked inside for lumps/cracks?

 

[JumbleDuck]

If you intend to get it done by a professional, do not let 'Fred who knows how to fibreglass' do it, get it done by a real FRP specialist.

Fred probably can do fibreglass OK, because a trained monkey can do fibreglass. However, Fred may well not be able to design the repair scheme suitably, and may benefit from a bit of supervision.

When I had a similar-ish problem with a 21' Westerly, I got a well-known naval architect to design a repair scheme which I could implement myself. He lived near the yard and called in every other day for the ten days or so the repair took to check how things were going. At the end of that he was willing to give a certificate saying that the job had been done to a satisfactory standard.

 

[30boat]

Fred probably can do fibreglass OK, because a trained monkey can do fibreglass. However, Fred may well not be able to design the repair scheme suitably, and may benefit from a bit of supervision.

When I had a similar-ish problem with a 21' Westerly, I got a well-known naval architect to design a repair scheme which I could implement myself. He lived near the yard and called in every other day for the ten days or so the repair took to check how things were going. At the end of that he was willing to give a certificate saying that the job had been done to a satisfactory standard.

If you can find an architect that'll be a great help but I think that with a bit of commonsense and some reading on the subject you can come up with a good layout for a strong repair.The main problem with these repairs is usually localized stresses hence my advice to taper any floors to nothing at the ends where they meet the hull sides.Or make them meet longitudinal stringers at approx 90º.That will spread the loads.

 

[CET1]

look for the book by Eric Green Associates Marine Composites Second Edition which is available on the internet. This may give you some pointers to your solution.

 

[JumbleDuck]

If you can find an architect that'll be a great help but I think that with a bit of commonsense and some reading on the subject you can come up with a good layout for a strong repair.

I agree. It also depends on the age of the boat. When I did mine she was only ten years old and worth repairing well enough to satisfy a finnicky purchaser ... though in the end I had her for another 20+ years. On an older boat will less value to lose it's probably fine to do something sensible and over-engineered.

The main problem with these repairs is usually localized stresses hence my advice to taper any floors to nothing at the ends where they meet the hull sides.

Yup, that's what I did. Five stainless steel floors, three feet long and tapering to points at the ends, bedded in and well covered with layup. That keel is going nowhere without the hull.